package com.seguridad.mac;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class GenerateSHA1 {

	public static String calculate(String text){
		byte[] sha1hash = new byte[40];
	    
		try {
	    	MessageDigest md = MessageDigest.getInstance("SHA-1");
		    md.update(text.getBytes("iso-8859-1"), 0, text.length());
			sha1hash = md.digest();
			
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	    
	    return convertToHex(sha1hash);
	    } 
	
	private static String convertToHex(byte[] data) { 
	    StringBuffer buf = new StringBuffer();
	    for (int i = 0; i < data.length; i++) { 
	        int halfbyte = (data[i] >>> 4) & 0x0F;
	        int two_halfs = 0;
	        do { 
	            if ((0 <= halfbyte) && (halfbyte <= 9)) 
	                buf.append((char) ('0' + halfbyte));
	        else 
	            buf.append((char) ('a' + (halfbyte - 10)));
	            halfbyte = data[i] & 0x0F;
	        } while(two_halfs++ < 1);
	    } 
	    return buf.toString();
	} 

}
